This invention relates to a lens holder driving device and, in particular, to an autofocus lens holder driving device for use in a compact camera.
Camera-equipped cellular mobile phones mount compact cameras therein. The compact camera is provided with an autofocus lens holder driving device. Previously, various autofocus lens holder driving devices have been proposed.
By way of illustration, Japanese Unexamined Patent Application Publication No. 2009-251031 (JP-A-2009-251031) (which will be also called Patent Document 1) discloses a lens driving device which is capable of decreasing a parts count and of miniaturizing. The lens driving device disclosed in Patent Document 1 comprises a lens holder in which a lens assembly can be mounted, a driving coil (a coil) fixed to the lens holder at outside circumstance thereof, a magnet opposite to the driving coil, an outer yoke including the magnet, an elastic member (an upper elastic member and a lower elastic member) for supporting the lens holder in a direction of an optical axis of the lens assembly shiftably, and a base disposed at a lower side of the lens holder. In Patent Document 1, the elastic member (the upper elastic member and the lower elastic member) is disposed in the inside of the outer yoke. The upper elastic member and the lower elastic member are called a front-side spring and a rear-side spring, respectively.
On the other hand, Japanese Unexamined Patent Application Publication No. 2009-014890 (JP-A-2009-014890) (which will be also called Patent Document 2) discloses a lens driving device in which a coil is energized from terminals through a rear-side spring. In the lens driving device disclosed in Patent Document 2, the rear-side spring comprises a ring-shaped spring as a whole and comprises one side portion (half body) and another side portion (half body) which are divided into both sides. The one side portion and the other side portions are electrically connected to one end and another end of the coil by means of solder or the like, respectively, thereby energizing to the coil from the rear-side spring. The one side portion constituting the rear-side spring is provided with a first terminal connection portion for connecting to a first terminal (a first electrode terminal) while the other side portion constituting the rear-side spring is provided with a second terminal connection portion for connecting to a second terminal (a second electrode terminal). Each terminal connection portion has a flat surface. One end (a tip) of the first terminal and the first terminal connection portion are bonded by means of a conductive thermosetting adhesive while one end (a tip) of the second terminal and the second terminal connection portion are bonded by means of a conductive thermosetting adhesive. Connections between the tips of the first and the second terminals and the first and the second terminal connection portions of the rear-side spring are not limited by the adhesive and may be connections such as fit or the like.
In the above-mentioned lens driving device disclosed in Patent Document 2, the one side portion of the rear-side spring is soldered to the one end of the coil while the other side portion of the rear-side spring is soldered to the other end of the coil. The rear-side spring is held by the lens holder. As a result, it is feared that the lens holder is susceptible to heat upon soldering (on electrically connecting the side portions of the rear-side spring to the ends of the coil).
In addition, in the lens driving device disclosed in Patent Document 2, the tip of the first terminal is bonded to the first terminal connection portion by means of the conductive thermosetting adhesive while the tip of the second terminal is bonded to the second connection portion by means of the conductive thermosetting adhesive. It is therefore disadvantageous in that it is necessary to cure the conductive thermosetting adhesive by heating it and it requires in time and effort. In addition, the first and the second terminal connection portions of the rear-side spring are mounted on the base. Accordingly, it is feared that the base is susceptible to heat upon heating the conductive thermosetting adhesive (on electrically connecting the terminal connection portions of the rear-side spring to the electrode terminals).